Low-Level Copper Plus Chitosan Applications Provide Protection Against Late Blight of Potato

Fig. 6. Effect of two commercially available products, chitosan-lactate (Chit-Lac) and CT-100, at varying concentrations on the development of potato late blight. Duplicate plants were treated with a 25 ml volume of spray mixture per plant. The chitosan lactate 1X concentration was 25 µg/ml and the CT-100 1X concentration was 18 µg/ml. The standard chitosan dissolved in acetic acid and neutralized is indicated as Chit 2X (50 µg/ml). Leaves were sprayed 3 days pre-inoculation. Seven sprayed leaves (49 leaflets) of each treatment were excised and each leaflet inoculated with P. infestans genotype US 8 (25 µl of a 20,000-sporangia-per-ml suspension) and incubated in 100% humidity at 16°C for 12 days. Values of percent symptomatic leaflet area with the same letter are not significantly different, based on a LSD0.05 = 7.01.



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Low-Level Copper Plus Chitosan Applications Provide Protection Against Late Blight of Potato